Drainage pipes having such seepage openings over part of their circumference have been known and available in commerce for over ten years. Because they have a single wall, they can be made of hard polyvinyl chloride (hard PVC). If the wall thicknesses are small, the waer seepage openings can be stamped. With wall thicknesses greater than 150 mm, the slit-like water seepage must be produced by sawing; as a necessary consequence, the seepage openings extend over from 25.degree. to 35.degree. of the circumference. These known pipes have several disadvantages. When a corrugated pipe segment is inserted into a sleeve embodied on the mating end of a corresponding pipe segment, the bottom surface of the pipe base arches inward, resulting in a leaky connection. Particularly with drainage pipe segments of relatively large wall thicknesses, however, sleeve connections which are watertight are required. Even if a sealing ring is also introduced into a groove, the connection is not tight. The shape stability of the pipes is generally reduced by the sawing of the relatively long, slit-like water seepage openings, which in turn again makes it more difficult to attain a firmly seated and completely tight sleeve connection. Furthermore, stones pressed into the pipe between the crests of the corrugations can cause the long slit-like seepage openings to spread apart substantially, allowing small stones and soil to get into the pipes; over the long run, this can result in complete clogging of the pipe. The only way to prevent such widening of the long slit-like seepage openings is to form the pipes such that the wall in the area of the openings is relatively thick; this, however, necessitates an undesirably high consumption of raw material.
It is true that double-walled drainage pipes, which comprise a corrugated outer pipe and a smooth inner pipe, do not have the above disadvantages; however, such double-walled pipes are extraordinarily expensive, particularly since they cannot be made of PVC, but can only be made of polyethylene.
From German laid-open application DE-OS 32 00 081 (corresponding to co-pending U.S. application No. 453,468), it is known to provide drainage pipes, both of the single-walled type discussed at the outset and the double-walled type that is smooth on the inside, with slit-like water seepage openings disposed in the troughs of the corrugations, extending over only a very short arc of the circumference and accordingly impairing the compression resistance of the crests of the corrugations, as well as the shape stability of the pipe, only slightly.